Fluid substances, be they liquid or semi-liquid, may be packaged by volume or by weight. It is generally preferred to package small volumes of heterogeneous substances by volume.
In general, volumetric packaging apparatus comprises a feed member, at least one positive displacement pumping member, at least one filler spout, and at least one dispenser member disposed so as to alternate between connecting the feed member to the pumping member and connecting the pumping member to the filler spout, the pumping member comprising a cylinder connected to the dispenser member, a piston mounted to slide inside the cylinder, and a drive rod fixed to the piston and connected to an actuator device.
When the substance is to be packaged aseptically, it is general practice to equip the pistons with piston rings and to supply the volume above the piston with a sterilizing liquid, generally sterile water with a bactericide. Since the piston rings can never provide perfect sealing, there is a danger of the sterilizing substance getting into the substance to be packaged during operation, and this poses problems of compatibility between the sterilizing substance and the substance to be packaged.
An object of the invention is to provide aseptic volumetric packaging apparatus in which there is no risk of the substance to be packaged being polluted in operation.
In addition, when the packaging apparatus includes a series of filler spouts mounted to move with the hopper, it is necessary when a sterilizing liquid is disposed above the pistons, for the sterilizing liquid to be conveyed by fixed pipework connected to the pistons via rotary seals which are complex and expensive.
Another object of the invention is to provide aseptic volumetric packaging apparatus having a simple structure for establishing a sterile barrier for a series of filler spouts.